Today the first and perhaps the only duty of the philosopher is to defend man against himself:
to defend man against that extraordinary temptation toward inhumanity to which
- almost without being aware of it - so many human beings today have yielded

Primary Sources:
The Philosophy of Existence, M. harari trans. (1948)
Problematic Man
The Mystery of Being: 1. Reflection and Mystery (1950-1)
The Mystery of Being: 2. Faith and Reality (1950-1)
Homo Viator: Introduction to a Metaphysic of Hope (1951)
Being and Having, K. Farrer trans. (1950)
The Existential Background of Human Dignity
Fresh Hope for the World
Creative Fidelity
Man Against Mass Society
Metaphysical Journal